Commit | Line | Data |
---|---|---|
8c50609b KB |
1 | /* |
2 | * Copyright (c) 1990 Regents of the University of California. | |
3 | * All rights reserved. | |
4 | * | |
5 | * %sccs.include.redist.c% | |
6 | */ | |
7 | ||
8 | #if defined(LIBC_SCCS) && !defined(lint) | |
f0a345ab | 9 | static char sccsid[] = "@(#)strtoul.c 5.3 (Berkeley) %G%"; |
8c50609b KB |
10 | #endif /* LIBC_SCCS and not lint */ |
11 | ||
12 | #include <limits.h> | |
13 | #include <ctype.h> | |
14 | #include <errno.h> | |
dd967b02 | 15 | #include <stdlib.h> |
8c50609b KB |
16 | |
17 | /* | |
18 | * Convert a string to an unsigned long integer. | |
19 | * | |
20 | * Ignores `locale' stuff. Assumes that the upper and lower case | |
21 | * alphabets and digits are each contiguous. | |
22 | */ | |
23 | unsigned long | |
24 | strtoul(nptr, endptr, base) | |
f0a345ab DS |
25 | const char *nptr; |
26 | char **endptr; | |
8c50609b KB |
27 | register int base; |
28 | { | |
f0a345ab | 29 | register const char *s = nptr; |
8c50609b KB |
30 | register unsigned long acc; |
31 | register int c; | |
32 | register unsigned long cutoff; | |
33 | register int neg = 0, any, cutlim; | |
34 | ||
35 | /* | |
36 | * See strtol for comments as to the logic used. | |
37 | */ | |
38 | do { | |
39 | c = *s++; | |
40 | } while (isspace(c)); | |
41 | if (c == '-') { | |
42 | neg = 1; | |
43 | c = *s++; | |
44 | } else if (c == '+') | |
45 | c = *s++; | |
46 | if ((base == 0 || base == 16) && | |
47 | c == '0' && (*s == 'x' || *s == 'X')) { | |
48 | c = s[1]; | |
49 | s += 2; | |
50 | base = 16; | |
51 | } | |
52 | if (base == 0) | |
53 | base = c == '0' ? 8 : 10; | |
54 | cutoff = (unsigned long)ULONG_MAX / (unsigned long)base; | |
55 | cutlim = (unsigned long)ULONG_MAX % (unsigned long)base; | |
56 | for (acc = 0, any = 0;; c = *s++) { | |
57 | if (isdigit(c)) | |
58 | c -= '0'; | |
59 | else if (isalpha(c)) | |
60 | c -= isupper(c) ? 'A' - 10 : 'a' - 10; | |
61 | else | |
62 | break; | |
63 | if (c >= base) | |
64 | break; | |
65 | if (any < 0 || acc > cutoff || acc == cutoff && c > cutlim) | |
66 | any = -1; | |
67 | else { | |
68 | any = 1; | |
69 | acc *= base; | |
70 | acc += c; | |
71 | } | |
72 | } | |
73 | if (any < 0) { | |
74 | acc = ULONG_MAX; | |
75 | errno = ERANGE; | |
76 | } else if (neg) | |
77 | acc = -acc; | |
78 | if (endptr != 0) | |
f0a345ab | 79 | *endptr = any ? s - 1 : (char *)nptr; |
8c50609b KB |
80 | return (acc); |
81 | } |